Graphene, a material for high temperature devices; intrinsic carrier density, carrier drift velocity, and lattice energy

TL;DR

This paper investigates graphene's potential for high-temperature devices by measuring its intrinsic carrier density, Fermi level, drift velocity, and phonon energy up to 2400 K, showing its advantages over traditional semiconductors.

Contribution

It provides the first comprehensive measurement of graphene's high-temperature electronic and phononic properties, demonstrating its suitability for high-temperature applications.

Findings

Intrinsic carrier density of graphene is less sensitive to temperature than Si or Ge.

Carrier drift velocity declines linearly with temperature.

Identified temperature coefficients of G mode phonon energy.

Abstract

Heat has always been a killing matter for traditional semiconductor machines. The underlining physical reason is that the intrinsic carrier density of a device made from a traditional semiconductor material increases very fast with a rising temperature. Once reaching a temperature, the density surpasses the chemical doping or gating effect, any p-n junction or transistor made from the semiconductor will fail to function. Here, we measure the intrinsic Fermi level (|E_F|=2.93k_B*T) or intrinsic carrier density (n_in=3.87*10^6 cm^-2 K^-2*T^2), carrier drift velocity, and G mode phonon energy of graphene devices and their temperature dependencies up to 2400 K. Our results show intrinsic carrier density of graphene is an order of magnitude less sensitive to temperature than those of Si or Ge, and reveal the great potentials of graphene as a material for high temperature devices. We also observe a linear decline of saturation drift velocity with increasing temperature, and identify the temperature coefficients of the intrinsic G mode phonon energy. Above knowledge is vital in understanding the physical phenomena of graphene under high power or high temperature.